Zhang Li, Shen Zhixue, Chen Yanwei, Ma Cuicui, Huang Mi, He Yueyue, Wang Guilan, Huang Dan, Su Bo, Jiang Boguang, Luo Yingjie, Li Wenfang, Lian Mao, Xu Xiaolong, Cheng Xingjun, Wang Zhenling
State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, China.
Core Facilities of West China Hospital, Sichuan University, Chengdu, China.
J Extracell Vesicles. 2025 Aug;14(8):e70151. doi: 10.1002/jev2.70151.
Many bacteria produce extracellular vesicles (EVs) that play critical roles in various biological processes and hold significant potential for biomedical applications. However, the mechanisms underlying EV biogenesis remain incompletely understood. Using transmission electron microscopy, we demonstrate that X-ray irradiation induces outward blebbing of the inner membrane in Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1), leading to the formation of outer-inner membrane vesicles (OIMVs) through outer membrane pinching-off. The endolysin Lys, which is negatively regulated by PrtR and positively regulated by PrtN, is essential for OIMV production. Lys translocates into the periplasmic space, where it disrupts the peptidoglycan layer, causing morphological changes from rod-shaped to round cells and facilitating OIMV release. Furthermore, deletion of YciB, a protein crucial for inner membrane integrity, significantly increases OIMV production. In a murine model of acute pneumonia, OIMV immunisation significantly improves pulmonary bacterial clearance, reduces lung injury and enhances survival rates. Our findings reveal inner membrane blebbing as a novel mechanism of OIMV biogenesis in P. aeruginosa PAO1 under X-ray irradiation and highlight the potential of OIMVs as promising vaccine candidates against P. aeruginosa infections.
许多细菌会产生细胞外囊泡（EVs），这些囊泡在各种生物过程中发挥着关键作用，并在生物医学应用方面具有巨大潜力。然而，EV生物发生的潜在机制仍未完全被理解。通过透射电子显微镜，我们证明X射线照射会诱导铜绿假单胞菌PAO1（P. aeruginosa PAO1）内膜向外起泡，导致通过外膜挤压形成外-内膜囊泡（OIMVs）。内溶素Lys由PrtR负调控，由PrtN正调控，对OIMV的产生至关重要。Lys转运到周质空间，在那里它破坏肽聚糖层，导致细胞形态从杆状变为圆形，并促进OIMV释放。此外，缺失对内膜完整性至关重要的蛋白质YciB会显著增加OIMV的产生。在急性肺炎小鼠模型中，OIMV免疫显著改善肺部细菌清除，减少肺损伤并提高存活率。我们的研究结果揭示了内膜起泡是X射线照射下铜绿假单胞菌PAO1中OIMV生物发生的一种新机制，并突出了OIMVs作为抗铜绿假单胞菌感染的有前景疫苗候选物的潜力。
